Temperature Sensors & Switches
About Temperature Sensors & Switches
Temperature sensors and switches tell the machine how hot the coolant is. A fan sensor or switch turns the radiator fan on at a set temperature, and an engine temperature sensor reports the coolant temperature to the fuel injection computer. This category lists Polaris radiator fan sensors and Polaris fuel injection water temperature sensors from Quad Logic.
If the fan never comes on, runs all the time, or the engine runs rough or starts hard when cold, a sensor can be the cause. Check the connector, wiring and coolant level first, then test the sensor as your service manual describes. The fan sensor and the fuel injection sensor are different parts even when they look alike, so choose the one for the job and for your model. Sensors screw into the coolant passage, so some coolant is lost on removal. Refill and bleed the system after fitting, using the sealing washer or O-ring the sensor needs.
Pick your machine in the Ride Finder at the top of the page. Related parts are Fans & Fan Parts, Thermostats & Housings and Water Pumps, all part of Engine Cooling.
FAQs on coolant temperature sensors and fan switches
What does a radiator fan sensor do?
A radiator fan sensor, or switch, detects the coolant temperature and turns the fan on when it reaches a set point. It turns the fan off again when the coolant cools. If it fails, the fan may never run or may run all the time.
How can I tell if a coolant temperature sensor is bad?
Signs include a fan that does not respond, a temperature reading that is wrong or erratic, rough running, or hard starting when cold. Check the connector and wiring first, and test the sensor with a meter as the service manual describes.
Do I have to drain the coolant to change a temperature sensor?
Usually some coolant will be lost, since the sensor sits in the coolant passage. Let the engine cool, catch what escapes, and top up with the correct coolant afterward. Bleed the air out and check for leaks.
Can I use a fan sensor from another model?
Do not assume that it will work. Sensors differ in thread size, connector and switching temperature, and the listings here are for Polaris models. Choose the sensor that is listed for your make, model and year.
